Vagus nerve stimulation (VNS) is a palliative surgical procedure used to treat refractory epilepsy. The present case involved a patient with mental retardation who had received a VNS implant for the treatment of refractory frontal lobe epilepsy in whom epileptic seizures during the induction of and recovery from general anesthesia were prevented by intentional stimulation of a VNS implant.
The patient was a 29-year-old man (height, 156 cm ; weight, 49 kg) who had been diagnosed as having mental retardation and refractory frontal lobe epilepsy. He had been started on oral antiepileptic drugs around the age of 14 years and had undergone VNS insertion at the age of 24 years. A VNS magnet setting mode was also available, allowing intentional stimulation when epileptic seizures were anticipated. Holding a proprietary magnet over the pulse generator for at least one second allowed 60 seconds of stimulation at an output current of 3.25 mA. The patient had been scheduled to undergo tooth extraction for the treatment of bilateral pericoronitis of the upper and lower wisdom teeth under general anesthesia.
Anticipating epileptic seizures during the induction of general anesthesia, we induced anesthesia while activating the magnet setting mode. General anesthesia was induced with propofol and rocuronium bromide, followed by right nasal intubation. No epileptic seizures occurred prior to muscle relaxation. The duration of the operation was 1 hour and 12 minutes. We administered sugammadex sodium once spontaneous respiration was resumed, resulting in a rapid increase in the BIS value and muscular rigidity in the upper extremities. The patient was allowed to recover from the anesthesia with the VNS magnet setting mode activated. No epileptic seizures were anticipated after the patient’s return to the ward.
Electrical stimulation of the left vagus nerve can exert an antiepileptic action by stabilizing the entire cerebral cortex via the solitary nucleus and by inhibiting aberrant excitatory neuronal activity. The electrodes are designed to transmit the stimulation current almost entirely on the central side, minimizing potential clinically problematic side effects such as bradycardia and hypotension. In the present patient, epileptic seizures were anticipated during the induction of and recovery from anesthesia, and activating the magnet setting mode successfully prevented any epileptic seizures from occurring. Our findings suggest that activating the magnet setting mode of VNS implants can effectively prevent epileptic seizures during the perioperative period and while under general anesthesia. However, since the main purpose of VNS is to prevent epileptic seizures, the use of antiepileptic drugs remains essential if an epileptic seizure occurs.
